Cyanidation of gold and silver in oxygen-enriched solution.

摘要

To better understand various factors influencing the dissolution kinetics of gold and silver in air saturated and oxygen enriched cyanide solutions, an extensive study has been carried out using the gold and silver rotating disc method. The dissolution behavior of gold and silver from their pure state and from Au-Ag alloys in cyanide solution has been investigated. The effect of solution pH, stirring speed of the disc, temperature, cyanide and oxygen concentrations, and sulfide minerals on the overall dissolution kinetics have been studied. Special emphasis has been given to the effects of the gold associated minerals such as pyrite, pyrrhotite, chalcocite, chalcopyrite, galena, sphalerite, molybdenite, pentlandite, arsenopyrite, and stibnite on gold and silver dissolution in atmospheric and oxygen enriched solutions.; The application of oxygen enriched cyanidation in three Canadian gold ore samples has been investigated. The results show that the use of oxygen can improve gold dissolution kinetics, reduce grinding time, increase pulp density and throughput accompanied by savings in cyanide and lime. Comparative studies of the CIP or CIPO process and the CIL or CILO process have also been conducted, which demonstrated that oxygen raised the rate of carbon adsorption by the oxidation of the carbon surface and formation of ion exchange sites which resulted in more favorable conditions for gold adsorption.; A general kinetic model has been derived from the cyanidation of the three distinct ore samples. (Abstract shortened by UMI.)